The so-called non-leaded package eliminating extension of leads from a resin package and exposing the leads (outer leads) on the lower surface of the resin package is known as a surface mount package.
A semiconductor device employing the non-leaded package has a structure obtained by sealing a semiconductor chip with a resin package along with a lead frame. The lead frame is formed by punching a thin metal plate, and includes an island and a plurality of leads arranged around the island. The semiconductor chip is die-bonded to the upper surface of the island, and electrically connected with each lead by a bonding wire extended between the surface thereof and the upper surface of each lead. The lower surfaces of the island and each lead are exposed on the rear surface of the resin package.